Carbonate diagenetic alteration

Reeckmann S.A. (1988) Diagenetic alterations in temperate shelf carbonates. Sediment. Geology 60, 209-219. 

Equation (6), the average oxidation states of carbon in these major constituents of biomass are -0.32, —1.67, —0.13, and 0.0, respectively. In contrast, when the atomic ratios for FAs, HAs, and NOM from the source data for Figure 4 are substituted into Equation (6), the median oxidation states of organic carbon in freshwater FAs, HAs, and NOM are calculated to be -hO.29, -hO.25, and -[-0.33, respectively. As expected from the loci of data points in Figure 5, freshwater FAs, HAs, and NOM differ only slightly from each other but are substantially more oxidized than the major constituents of biomass. These data are consistent with the early diagenetic alteration of biomass, in... 

Several common local sorption processes have been examined here by way of illustrating such effects sorption by geologically immature soft-carbon organic matter, which results in quasi-linear sorption isotherms, sorption by common mineral phases within concentration regions where linear behavior is exhibited, and sorption by diagenetically altered hard-carbon organic matter... 

Feldspar averages 3.5% (range 0-8%) and is predominantly plagioclase. Microcline is rare. Most grains show signs of dissolution and diagenetic alteration (replacement by carbonate). 

Although the ratio of 180 160 in carbonate tests of marine invertebrates can be used to examine sea surface temperatures, the extent of continental glaciation, the balance between precipitation and evaporation, the carbonate compensation depth and the diagenetic alteration of carbonate all influence whether an estimation can be made and its accuracy (Boxes 5.6, 5.7 Marshall 1992). There is also a reliable organic geochemical palaeothermometer based on the distributions of long-chain (C37-C39) unsaturated ketones (Brassell et al. 

---